1. Field of the Invention
The invention relates to a method for manufacturing an image sensor, and in particular to a method for effectively removing particles and improving the sensor effects.
2. Description of the Related Art
A general sensor is used to sense signals, which may be optical or audio signals. The sensor of the invention is used to receive image signals or optical signals. After receiving the image signals, the sensor converts the image signals into electrical signals, which are then transmitted to a printed circuit board via a substrate.
Referring to FIG. 1, a conventional image sensor includes a substrate 10, a frame layer 18, a photosensitive chip 26, a plurality of wires 28, and a transparent layer 34. The substrate 10 has an upper surface 12 on which first terminals 15 are formed, and a lower surface 14 on which second terminals 16 are formed. The frame layer 18 has a first surface 20 and a second surface 22 adhered to the upper surface 12 of the substrate 10 to form a cavity 24 together with the substrate 10. The photosensitive chip 26 is arranged within the cavity 24 and is mounted to the upper surface 12 of the substrate 10. Each wire 28 has a first terminal 30 and a second terminal 32. The first terminals 30 are electrically connected to the photosensitive chip 26, and the second terminals 32 are electrically connected to the first terminals 15 of the substrate 10. The transparent layer 34 is adhered to the first surface 20 of the frame layer 18.
However, the image sensor has to be manufactured in a clean room in order to prevent particles from entering the cavity 24, to prevent electrostatic charges from adhering to the transparent layer 34 and the photosensitive chip 26, and to increase the number of good pixels. Even if the image sensor is manufactured in a clean room, a few particles may enter the cavity 24 to influence the quality of the pixels of the image sensor. Thus, the manufacturers have to spend a lot of money to heighten the level of the clean room so as to prevent any particles from entering the image sensor.